PS Engineering PAR200 - Manual (Page 10)

PS Engineering Inc. ®
PAR200 Audio Selector Panel, COM radio Controller and Intercom System
Installation and Operator’s Manual
200-228-0000 Page 2-3 Rev. 4, Dec. 2013
Ground loop noise occurs when there are two or more ground paths for the same signal (i.e., airframe and
ground return wire). Large cyclic loads such as strobes, inverters, etc., can inject noise signals onto the
airframe that are detected by the audio system. Follow the wiring diagram very carefully to help ensure a
minimum of ground loop potential. Use only Mil Spec shielded wires (MIL-C-275000, or better). Under
no circumstances combine a microphone and headphone wiring into the same shielded bundle. Always
use a 2- or 3-conductor, shield wire as shown on the installation-wiring diagram.
The shields can be daisy-chained together, and then connected to the ground lugs mounted on the center
of the back plate.
Radiated signals can be a factor when low level microphone signals are "bundled" with current carrying
power wires. Keep these cables physically separated. It is very important that you use insulated washers to
isolate the ground return path from the airframe to all headphone and microphone jacks.
2.4.1.1 Music Inputs and Noise
PAR200 units utilize differential music inputs to help prevent noise from entering the music system. This
feature is usually transparent to the installer, however, it is important that the appropriate music signal
and ground connections are made directly to the dedicated music signal and ground inputs on the
PAR200. The power for IFE and audio panel should be a common bus.
If a music jack is installed for Music 1 or 2, we strongly recommend isolating the jack from airframe
ground, by using an insulated mounting plate.
NOTE
Adding a high-performance audio control system, particularly in conjunction with high-performance ac-
tive noise canceling headsets, cannot improve on older avionics that were designed for cabin-speaker use.
PS Engineering makes no claim that the audio panel will provide a noise-free audio quality under all in-
stallation conditions, particularly with older avionics.
2.4.2 Audio Panel Tray and Connector Assembly
The rack connectors mate with two 44-pin connectors in the PAR200. The connectors are a sub-miniature
crimp-type, and require the use a hand crimp tool, from table below (or equiv.). The connectors are
mounted to the tray back plate with #4-40 screws (475-440-1038), from the inside of the tray and the
mounting block, 431-891-0100. Ensure that proper strain relief and chafing precautions are made during
wiring and installation, using the cable clamp (625-001-0002).
Manufacturer Crimping Tool Positioner Extraction tool
AMP 601966-1 601966-6 91067-1
Daniels AFM8 K42 M24308-1
ITT-Cannon 995-0001-584 995-0001-739 91067-1
Table 2-1 PAR200 Connector Pin crimping tools
Manufacturer Crimping Tool Positioner Extraction tool
Mil-Spec M22520/2-01 M22520/2-08
Daniels AFM8 K13-2
Table 2-2 TY91 Connector Crimping tools
2.4.3 Audio Panel interface
The PAR200 is designed to interface with standard aircraft avionics, and presents a 500  receiver im-
pedance. For best results, a twisted-shielded cable is recommended from the avionics audio source to the
audio panel, with the shield grounded at the audio panel end.
Inputs N1 and N2 can be used to control navigation receiver audio, J1 Pins 17 WRT 18 and J1 19 WRT
20, respectively.